EP2420178A1 - Endoscope device and endoscope - Google Patents

An endoscope includes a side viewing observation section and a forward viewing observation section provided on a distal end side of an insertion portion which is inserted into an observation target for acquiring subject images of an observation target in a circumferential direction and an insertion direction of the insertion portion, respectively, a protruding member that passes within a viewing field of the side viewing observation section and protrudes closer to the distal end side than the side viewing observation section; and a shielding section located within a viewing field of the side viewing observation section, which shields light entering the side viewing observation section in a range in which the protruding member passes.

Technical Field

• The present invention relates to an endoscope apparatus and an endoscope that enable forward viewing and side viewing observations.

Background Art

• Endoscopes provided with illumination means and observation means on a distal end side of an insertion portion have been widely used in the medical and other fields in recent years.

• The insertion portion of the endoscopes may be inserted into a tubular organ and used to inspect the inner wall thereof. To facilitate an inspection in such a case, endoscopes are being developed which are provided with not only a forward viewing field whose observation viewing field is a front side (distal end side) of the insertion portion along the axial direction (insertion direction) of the insertion portion but also a side viewing field whose observation viewing field is a side direction which is a side of the insertion portion or circumferential direction.

• Japanese Patent Application Laid-Open Publication No.

  2000-116598

  as a first related art is provided with both viewing fields, but the side viewing field can only observe a range centered on a predetermined direction in a circumferential direction of the entire perimeter of 360°. Therefore, in order to perform inspection on the entirety of a tubular inner wall, it is necessary to rotate the insertion portion in the circumferential direction over a wide range.

• Accordingly, there is a desire for an endoscope having a wide-angle side viewing field which covers almost entire sideward perimeter without a need for wide-range rotation.

• Japanese Patent Application Laid-Open Publication No.

  2008-309860

  as a second related art discloses an optical system of an endoscope provided with an optical system rotationally symmetric with respect to a central axis forming a forward viewing optical path that picks up an image of an object in the central axis direction and a wide-angle side viewing optical path (side viewing observation section) that produces at least two reflections in a ring-shaped optical device and forms an omnidirectional (entire sideward perimeter) ring-shaped image outside the circular image of the forward viewing optical path on the same image pickup device.

• Furthermore, International Publication No.

  W02006/004083

  as a third related art discloses an endoscope attachment attached to a distal end portion of an endoscope provided with a forward viewing observation section and a wide-angle side viewing observation section.

• The third related art describes a light-shielding structure to prevent illuminating light from entering the side viewing observation section.

• In a case where a wide-angle side viewing observation section is formed as in the second and the third related arts, if a nozzle for cleaning the forward viewing observation window by washing adherents stuck thereto, for example, is provided, there is such a defect that the nozzle enters into the side viewing field, thereby interfering with an excellent observation.

• Specifically, it is necessary to arrange the nozzle for removing adherents on the forward viewing observation window or a conduit which passes liquid to the nozzle (hereinafter, generically referred to as nozzle) at a distance near the side viewing observation window in the side viewing field of the wide-angle side viewing observation window. As a result, the image of the nozzle stands out in a side viewing field image.

• Since such a nozzle is not originally an observation target by the side viewing observation window, it is desirable to prevent the nozzle from appearing in a side viewing field image when an excellent side viewing field image is intended to be formed.

• In addition, in a case of an endoscope apparatus including a light adjusting function for automatically adjusting quantity of light of illumination light according to the luminance level based on a picked-up image signal, the luminance level of the image signal (video signal) is affected not only by the image of an original observation target but also by the image of the nozzle which appears on a short-distance side viewing field image, which results in an decrease in the light adjusting function.

• Furthermore, in a case of an endoscope provided with a channel through which a treatment instrument is inserted for enabling the treatment instrument to be used, there is a case where an operator performs a treatment by protruding the treatment instrument from the channel. In this case, when the treatment instrument is protruded, the treatment instrument appears on a side viewing field image similarly as the above-described nozzle, which sometimes causes a decrease in the light adjusting function.

• In the second and the third related arts, it is difficult to solve the above-described defects when the nozzle is provided.

• Note that in

  FIG. 2

  in the third related art, a mirror 171 which prevents illumination light from entering into the side viewing observation window is disclosed. However, the mirror 171 shields only a part of the optical path of the illumination light, and the mirror does not shield (block) the side viewing field from light as known from the fact that the mirror is arranged outside the side viewing field.

• The present invention has been achieved in view of the above-described points, and an object of the present invention is to provide an endoscope apparatus and an endoscope which are capable of preventing a protruding member such as a nozzle appearing in a side viewing field from appearing on an endoscope image such as a side viewing field image.

Disclosure of Invention Means for Solving the Problem

• An endoscope apparatus according to the present invention includes an insertion portion inserted into an observation target, a side viewing observation section provided on a distal end side of the insertion portion for acquiring a subject image of an observation target in a circumferential direction of the insertion portion, a forward viewing observation section provided closer to the distal end side than the side viewing observation section of the insertion portion for acquiring a subject image of an observation target in an insertion direction of the insertion portion, a protruding member that passes within a viewing field of the side viewing observation section and protrudes closer to the distal end side than the side viewing observation section; an image processing apparatus that generates a side viewing observed image and a forward viewing observed image to be displayed as observed images based on the subject image in the circumferential direction obtained from the side viewing observation section and the subject image in the insertion direction obtained from the forward viewing observation section, and a shielding section that electrically or mechanically shields a display of a subject image of an observation target in a range in which the protruding member is located on the side viewing field image, when the observed images generated by the image processing apparatus are displayed.

• An endoscope according to the present invention includes an insertion portion inserted into an observation target, a side viewing observation section provided on a distal end side of the insertion portion for allowing light from the observation target in a circumferential direction of the insertion portion to enter and acquiring a subject image, a forward viewing observation section provided closer to the distal end side than the side viewing observation section in the insertion portion for allowing light from the observation target in an insertion direction of the insertion portion to enter and acquiring a subject image, a protruding member that passes within a viewing field of the side viewing observation section and protrudes closer to the distal end side than the side viewing observation section, and a shielding section located within a viewing field of the side viewing observation section, which shields light entering the side viewing observation section in a range in which at least the protruding member passes within the side viewing field.

Brief Description of the Drawings
• Fig. 1 is a perspective view illustrating an endoscope apparatus according to a first embodiment of the present invention;
• Fig. 2 is a perspective view illustrating a configuration of a distal end portion of an insertion portion of the endoscope;
• Fig. 3 is a front view illustrating a configuration of the distal end portion of the insertion portion;
• Fig. 4 is a cross-sectional view illustrating a perimeter of the objective optical system on an O-B cross section in Fig. 3 and a structure of the side viewing illuminating window;
• Fig. 5 is a diagram illustrating a protruding member such as a forward viewing observation window nozzle section arranged inside the shielding member according to a C-D cross section in Fig. 3;
• Fig. 6 is a diagram illustrating an example of an endoscope image according to the first embodiment;
• Fig. 7 is a perspective view illustrating a configuration of a distal end portion according to a second embodiment of the present invention;
• Fig. 8 is a front view illustrating a configuration of the distal end portion;
• Fig. 9 is a diagram illustrating an example of an endoscope image according to the second embodiment;
• Fig. 10 is a perspective view illustrating a configuration of a distal end portion according to a third embodiment of the present invention;
• Fig. 11 is a front view illustrating a configuration of the distal end portion;
• Fig. 12 is a diagram illustrating an example of an endoscope image according to the third embodiment;
• Fig. 13 is a perspective view illustrating a configuration of a distal end portion according to a modification example of the third embodiment;
• Fig. 14 is a front view illustrating a configuration of a distal end portion according to a fourth embodiment of the present invention;
• Fig. 15 is a block diagram illustrating a schematic configuration of the endoscope apparatus;
• Fig. 16A is a diagram illustrating an example of endoscope image when mask processing is set to OFF;
• Fig. 16B is a diagram illustrating an example of endoscope image when mask processing is set to ON; and
• Fig. 17 is a diagram illustrating an example of endoscope image when set to mask processing corresponding to arrangement information of a protruding member.
Best Mode for Carrying Out the Invention

• Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

(First embodiment)

• As shown in

  Fig. 1

  , an

  endoscope apparatus

  1 according to a first embodiment of the present invention has an endoscope 2 that performs endoscopy. The endoscope 2 is configured by including an

  operation section

  3 grasped and operated by a surgeon, an

  elongated insertion portion

  4 formed at a front end of the

  operation section

  3 and inserted into an observation target such as the body cavity and a

  universal cord

  5, a proximal end of which extends from one side of the

  operation section

  3.

• Furthermore, the

  insertion portion

  4 is made up of a rigid

  distal end portion

  6 provided at a distal end thereof, a

  bendable bending portion

  7 provided at a rear end of the

  distal end portion

  6 and a long

  flexible tube portion

  8 provided at a rear end of the

  bending portion

  7 and the

  bending portion

  7 can be bent using a

  bending operation lever

  9 provided at the

  operation section

  3.

• Furthermore, as shown in

  Fig. 2

  , a

  cylindrical portion

  10 protruding in a cylindrical shape from a distal end face of the

  distal end portion

  6 at a position, for example, decentered upward from the center thereof is formed in the

  distal end portion

  6 of the

  insertion portion

  4. An objective optical system 11 (see

  Fig. 4

  ) for both forward viewing and side viewing optical observations is provided in a distal end portion of the

  cylindrical portion

  10, a forward

  viewing observation window

  12 as a forward viewing observation section and a side

  viewing observation window

  13 as a side viewing observation section are formed and a side viewing

  illuminating window

  14 is formed in the vicinity of a proximal end of the

  cylindrical portion

  10.

• The side

  viewing observation window

  13 has a side viewing field formed to have a wide angle so as to cover the entire perimeter in the side direction along a substantially ring-shaped side direction in the cylinder-shaped

  cylindrical portion

  10 and is provided with a

  mirror lens

  15 as a reflection optical system for capturing light from the subject within the side viewing field into the side viewing field and acquiring the light as a side viewing field image.

• Furthermore, a forward viewing

  illuminating window

  16 that emits illuminating light to the observation target side corresponding to the forward viewing field of the forward

  viewing observation window

  12 neighboring the

  cylindrical portion

  10 for illumination and a channel distal

  end opening portion

  17 that serves as a distal end opening that allows a treatment instrument inserted in a channel to protrude are provided on the distal end face of the

  distal end portion

  6.

• Furthermore, in the present embodiment, a

  support portion

  18 is provided neighboring, for example, a lower position in a circumferential direction of the

  cylindrical portion

  10 so as to protrude from the distal end face of the

  distal end portion

  6 to generate an excellent side viewing field image.

• The

  support portion

  18 is provided with a

  shielding section

  18a that optically shields a protruding member making up the endoscope 2 which protrudes from the distal end face and which is not an original observation target, to prevent the protruding member from appearing within the side viewing field and being acquired as a side viewing field image.

• The

  support portion

  18 supports (or holds) a forward viewing observation

  window nozzle portion

  19 as a nozzle for cleaning the forward

  viewing observation window

  12 that protrudes from the distal end face of the

  distal end portion

  6 and constitutes a protruding member appearing within the side viewing field and a forward viewing

  illuminating window

  21 that likewise constitutes a protruding member, and shields the forward viewing observation

  window nozzle portion

  19 and the forward viewing

  illuminating window

  21 with the

  shielding section

  18a so as not to appear in the side viewing field image.

• Furthermore, the

  support portion

  18 supports a side viewing observation

  window nozzle portion

  22, a distal end of which protrudes from the side of the

  support portion

  18 and opens to face the side

  viewing observation window

  13 to function as a nozzle for cleaning the side

  viewing observation window

  13 and also shields the side viewing observation

  window nozzle portion

  22 so as not to appear in a side viewing field image. As shown in

  Fig. 3

  , the side viewing observation

  window nozzle portion

  22 is provided in two locations.

• The

  operation section

  3 shown in

  Fig. 1

  is provided with a gas/liquid

  feeding operation button

  24 so as to allow the forward viewing observation

  window nozzle portion

  19 and the side viewing observation

  window nozzle portion

  22 to selectively inject a cleaning gas or liquid and the surgeon can switch between feeding gas and feeding liquid by operating the gas/liquid

  feeding operation button

  24.

• Although

  Fig. 1

  illustrates an example where one gas/liquid

  feeding operation button

  24 is provided, the function may be assigned to a

  scope switch

  25 provided at the top of the

  operation section

  3.

• Furthermore, the

  operation section

  3 is provided with a

  suction operation button

  26 to suction and recollect mucus or the like in the body cavity through the channel distal

  end opening portion

  17. The channel is formed of a tube (not shown) or the like disposed in the

  insertion portion

  4 and communicates with a treatment

  instrument insertion port

  27 provided near the front end of the

  operation section

  3.

• When performing a treatment using the treatment instrument, the surgeon inserts the treatment instrument from the treatment

  instrument insertion port

  27, causes a distal end side thereof to protrude from the channel distal

  end opening portion

  17 and can thereby perform a treatment using the treatment instrument.

• Furthermore, a

  connector

  29 is provided at an end of the

  universal cord

  5 and the

  connector

  29 is connected to a

  light source apparatus

  31 of the endoscope. A pipe sleeve (not shown) which is a connection end of a fluid conduit protruding from a distal end of the

  connector

  29 and a light guide pipe sleeve (not shown) which is a supply end for illuminating light are detachably connected to the

  light source apparatus

  31 and one end of a

  connection cable

  33 is connected to an electric contact portion provided on the side.

• Furthermore, the connector of the other end of the

  connection cable

  33 is electrically connected to a

  video processor

  32 as a signal processing apparatus or image processing apparatus that performs signal processing or image processing with respect to an

  image pickup device

  34 mounted in the endoscope 2.

• The

  video processor

  32 supplies a drive signal for driving the image pickup device 34 (see

  Fig. 4

  ) mounted in the

  distal end portion

  6 of the endoscope 2, performs signal processing on an image pickup signal (image signal) outputted from the

  image pickup device

  34 with the supplied drive signal and generates a video signal.

• The video signal generated by the

  video processor

  32 is outputted to a

  monitor

  35 as a display apparatus and an image picked up by the

  image pickup device

  34 is displayed on the display surface of the

  monitor

  35 as an endoscope image. The peripheral apparatuses such as the

  light source apparatus

  31, the

  video processor

  32 and the

  monitor

  35 are arranged on a

  stand

  37 together with a

  keyboard

  36 for inputting patient information or the like.

• The illuminating light generated by the

  light source apparatus

  31 is transmitted through a light guide passed from the

  universal cord

  5 through the

  operation section

  3 and the

  insertion portion

  4, radiated, radiatively spread out from the side

  viewing illuminating window

  14 of the

  cylindrical portion

  10 protruding from the

  distal end portion

  6, the forward

  viewing illuminating window

  16 and the forward viewing illumination section 19 (provided in the support portion 18) in the side direction and the insertion direction respectively so as to be able to illuminate a subject side such as a diseased part.

• Fig. 4

  illustrates an O-B cross section of

  Fig. 3

  , that is, a configuration of peripheral sections of the objective

  optical system

  11 which has dual forward viewing and side viewing functions, and the side

  viewing illuminating window

  14.

• The objective

  optical system

  11 is formed on the optical axis that coincides with the image pickup center O along the central axis of the

  cylindrical portion

  10 protruding from the

  distal end portion

  6, made up of a

  front lens

  41, the

  mirror lens

  15 and a

  rear lens group

  43, each of which is rotationally symmetric, being arranged to form an image on the

  image pickup device

  34. A

  cover glass

  34a is provided in front of the

  image pickup device

  34.

• The

  front lens

  41 provided in the forward

  viewing observation window

  12 as a circular forward viewing observation section at the distal end of the

  cylindrical portion

  10 forms a wide-angle forward viewing field whose front side along the axial direction (insertion direction) of the

  insertion portion

  4 corresponds to an observation viewing field.

• The

  mirror lens

  15 arranged immediately behind the

  front lens

  41 is made up of two joined lenses and reflects light incident from the side twice by the joining surface and the front surface, and guides the reflected light to the

  rear lens group

  43.

• Using the

  mirror lens

  15 provided in the side

  viewing observation window

  13, the side

  viewing observation window

  13 forms a quasi-ring-shaped observation viewing field that covers the entire perimeter in the insertion portion circumferential direction while maintaining a predetermined viewing angle substantially centered on the optical axis in the side viewing direction with respect to the insertion portion longitudinal axis direction.

• As is obvious from

  Fig. 4

  , the forward

  viewing observation window

  12 protrudes from the distal end face of the

  distal end portion

  6 of the

  insertion portion

  4 toward the distal end side more than the side

  viewing observation window

  13 does.

• Fig. 4

  schematically shows paths of a light beam entering the

  front lens

  41 forming the forward

  viewing observation window

  12 from the subject side in the viewing field thereof and a light beam entering the

  mirror lens

  15 forming the side

  viewing observation window

  13 from the subject side in the viewing field thereof.

• A subject image by light from the subject entering the viewing field of the

  front lens

  41 of the forward

  viewing observation window

  12 is formed in a circular shape in the center of the image pickup surface of the

  image pickup device

  34 and acquired as a forward viewing field image. Furthermore, a subject image by light from the subject entering the viewing field of the

  mirror lens

  15 facing the side

  viewing observation window

  13 is formed in a ring shape on the circumferential side of the forward viewing field image and acquired as a ring-shaped side viewing field image.

• However, in the present embodiment, the

  shielding section

  18a of the

  support portion

  18 mechanically shields part of ring-shaped side viewing field image as will be described later.

• Furthermore, a distal end side of a

  light guide

  44 as a light guide member for side viewing illumination is arranged on the peripheral side of the

  cylindrical portion

  10, a

  light guide groove

  45 is formed extending in a belt shape in the circumferential direction of the

  cylindrical portion

  10 centered on a position that a distal end face of the

  light guide

  44 faces and the

  light guide groove

  45 is formed by arranging a

  reflection member

  46 with a

  concave reflection section

  46a provided in a notched recessed part for forming the

  light guide groove

  45.

• The

  light guide

  44 and the

  light guide groove

  45 formed of the

  reflection member

  46 are arranged in a plurality of locations along the circumferential direction of the

  cylindrical portion

  10. In this case, the distal end face of the

  light guide

  44 as a light guide member is located near the center position in the circumferential direction of each

  reflection member

  46 making up the

  light guide groove

  45 formed in a belt shape along the circumferential direction of the

  cylindrical portion

  10.

• The light exited from the distal end face as a light exit end face of the

  light guide

  44 is reflected by the

  reflection section

  46a of the inner surface of the reflection member 46 (inner surface of the light guide groove 45) and the illuminating light is exited at a wide angle in the side direction in which the

  light guide groove

  45 is provided.

• The side

  viewing illuminating window

  14 which exits the side viewing illuminating light over a wide range in the side direction is then formed of the

  light guide groove

  45 made up of a plurality of light guides 44 and

  reflection member

  46. Therefore, the observation target side portion corresponding to the viewing field of the entire perimeter in side direction which can be observed through the side

  viewing observation window

  13 can then be illuminated with illuminating light exited from the side

  viewing illuminating window

  14.

• Furthermore, in the present embodiment, the forward viewing observation

  window nozzle portion

  19 or the like disposed along the side

  viewing observation window

  13 is supported by the

  support portion

  18 and also shielded with respect to the side viewing field so as to be able to acquire an excellent side viewing field image.

• As shown in

  Fig. 2 and Fig. 3

  , the

  support portion

  18 has a substantially rectangular parallelepiped shape and is formed such that the rectangular parallelepiped top surface side portion contacts the side portion at the bottom end of the

  cylindrical portion

  10.

• The

  shielding section

  18a (see

  Fig. 2

  ) provided opposed to the side

  viewing observation window

  13 so as to block the side

  viewing observation window

  13 in the

  support portion

  18 has a shielding function. The

  support portion

  18 may be metal such as stainless steel forming the

  distal end portion

  6 or may also be formed using resin such as polysulfone resin or the stainless steel outer circumferential side part may be covered with resin.

• Furthermore, in the case of resin such as polysulfone resin, the

  shielding section

  18a portion facing the side

  viewing observation window

  13 may be made of a material containing a black paint to enhance the function of shielding light or the

  entire support portion

  18 may have a black color.

• The

  support portion

  18 in the present embodiment not only has the function of shielding the protruding member such as the forward viewing observation

  window nozzle portion

  19 or the like so as not to appear within the side viewing field of the side

  viewing observation window

  13 but also supports the protruding member such as the forward viewing observation

  window nozzle portion

  19 or the like and increases its mechanical strength.

• For this reason, the present embodiment adopts a configuration in which the forward viewing observation

  window nozzle portion

  19 or the like is arranged inside the

  support portion

  18. As will be described later, a configuration provided only with the shielding function as in the case of embodiments may be adopted.

• In the interior of the

  support portion

  18, a gas/

  liquid feeding conduit

  19a is arranged as shown in

  Fig. 5

  and a forward viewing

  observation window nozzle

  19b which is bent in an L-figure shape and opens in the direction of the forward

  viewing observation window

  12 side is provided at a distal end of the gas/

  liquid feeding conduit

  19a and the forward viewing observation

  window nozzle portion

  19 is formed.

• The forward viewing

  observation window nozzle

  19b changes the injection direction of gas or liquid sent from the gas/

  liquid feeding conduit

  19a side to a substantially right angle direction, injects the gas or liquid to the forward

  viewing observation window

  12 side to thereby wash adherents such as body fluid stuck to the forward

  viewing observation window

  12 off the forward

  viewing observation window

  12 and restore the forward

  viewing observation window

  12 to a clean state.

• Furthermore, a

  light guide

  21a is arranged as a light guide member for illuminating light neighboring the forward viewing observation

  window nozzle portion

  19 inside the

  support portion

  18 and an

  illumination lens

  21b is arranged at a distal end face of the

  light guide

  21a, the

  light guide

  21a and the

  illumination lens

  21b forming the forward

  viewing illuminating window

  21. The distal end side portion of the

  light guide

  21a and the

  illumination lens

  21b are fixed inside a

  tubular base

  21c.

• Light exited from the distal end face of the

  light guide

  21a is made to exit from the forward

  viewing illuminating window

  21 through the

  illumination lens

  21b to the forward side thereof as illuminating light to illuminate the subject on the forward viewing field side of the forward

  viewing observation window

  12. The distal end face of the

  support portion

  18 is formed so as to be substantially positioned on the same surface with the distal end face of the

  cylindrical portion

  10.

• The side viewing observation

  window nozzle portion

  22 is also made up of a gas/liquid feeding conduit (not shown) and a side viewing

  observation window nozzle

  22b that opens toward the side

  viewing observation window

  13 provided at a distal end thereof. The side viewing

  observation window nozzle

  22b protrudes from the side surface of the

  support portion

  18, but is mechanically shielded by the

  shielding section

  18a (see

  Fig. 2

  ) formed so as to block the side

  viewing observation window

  13 in the

  support portion

  18 to prevent the side viewing

  observation window nozzle

  22b from being acquired as a side viewing field image.

• The

  shielding section

  18a mechanically shields an angle of α around an image pickup center O in the circumferential direction as shown in

  Fig. 3

  , and the forward viewing observation

  window nozzle portion

  19, the forward

  viewing illuminating window

  21 and the side viewing observation

  window nozzle portion

  22 are arranged as protruding members within this angle α.

• The endoscope 2 of the present embodiment having such a configuration is provided with the side

  viewing observation window

  13 as a side viewing observation section for acquiring a subject within a side viewing field formed at a wide angle along the circumferential direction of the

  insertion portion

  4 on the distal end side of the

  insertion portion

  4 as a side viewing field image and the forward

  viewing observation window

  12 provided closer to the distal end side than the side

  viewing observation window

  13 in the

  insertion portion

  4 as a forward viewing observation section for acquiring a subject within the forward viewing field along the axial direction of the

  insertion portion

  4 as a forward viewing field image.

• Furthermore, the endoscope 2 is provided with the forward viewing observation

  window nozzle portion

  19 as a protruding member protruding toward the distal end side more than the side

  viewing observation window

  13 passing through the side viewing field by the side

  viewing observation window

  13, the forward

  viewing illuminating window

  21, the side viewing observation

  window nozzle portion

  22 and the

  shielding section

  18a that shields the light from a range (predetermined range) in which at least the protruding member within the side viewing field passes so as not to enter the side viewing field (or side viewing observation section).

• Fig. 6

  shows a display example where a subject image picked up by the

  image pickup device

  34 using the endoscope 2 is displayed on a

  display surface

  35a of the

  monitor

  35 as an endoscope image.

• A rectangular region 51 in

  Fig. 6

  corresponds to a display region of the image pickup surface of the

  image pickup device

  34. A center circular region of the rectangular region 51 corresponds to a

  display region

  52 of the forward viewing field image by the forward

  viewing observation window

  12 and a ring-shaped region outside the

  display region

  52 corresponds to a

  display region

  53 of a side viewing field image by the side

  viewing observation window

  13.

• Furthermore, a region where the

  shielding section

  18a of the

  support portion

  18 mechanically shields part of the side viewing field is formed as a shielding

  region

  54 in the side viewing field image. The shielding

  region

  54 is a region corresponding to the angle α in

  Fig. 3

  around the image center O' corresponding to the image pickup center O in

  Fig. 3

  .

• The surgeon can smoothly inspect a tubular organ or the like by observing an endoscope image.

• According to the endoscope 2 of the present embodiment, the

  shielding section

  18a provided in the

  support portion

  18 can shield the light from the forward viewing observation

  window nozzle portion

  19, the forward

  viewing illuminating window

  21 and the side viewing observation

  window nozzle portion

  22, which are protruding members as components of the endoscope 2 different from the original observation targets, appearing within the side viewing field of the side

  viewing observation window

  13 so as not to be acquired as a side viewing field image. The endoscope 2 of the present embodiment can shield the protruding members different from the original observation targets and can acquire a side viewing field image corresponding to the original observation target.

• Furthermore, according to the present embodiment, even when an image signal of the

  image pickup device

  34 is used for automatic light adjustment, a light adjustment signal for automatic light adjustment can be generated from an image signal not affected by the protruding members, and automatic light adjustment can thereby be effectively used without deterioration of the function.

(Second embodiment)

• Next, a second embodiment of the present invention will be described.

  Fig. 7

  shows a perspective view of a structure in the vicinity of a distal end of an

  insertion portion

  4 of an endoscope of the second embodiment of the present invention and

  Fig. 8

  illustrates a front view thereof.

• The present embodiment basically has a configuration equivalent to the endoscope 2 of the first embodiment with the

  distal end portion

  6 partially modified. There are provided a

  cylindrical portion

  10 protruding in a cylindrical shape from a center position of the distal end face and a

  support portion

  18 provided with a

  shielding section

  18a that supports protruding members such as a forward viewing observation

  window nozzle portion

  19 and shields (provides light-shielding of) the protruding members so as not to appear within a side viewing field of a side

  viewing observation window

  13 on the distal end face of the

  distal end portion

  6.

• As with the first embodiment, the

  cylindrical portion

  10 is provided with a forward

  viewing observation window

  12, the side

  viewing observation window

  13 and a side

  viewing illuminating window

  14. The present embodiment shows an example where the outside diameter of the side

  viewing illuminating window

  14 is the same as the outside diameter of the side

  viewing observation window

  13, but the outside diameters may be different. Furthermore, in the present embodiment, the side

  viewing illuminating window

  14 is configured to be able to illuminate the entire sideward perimeter. Of course, the same configuration as that of the first embodiment may also be adopted.

• In the first embodiment, the channel distal

  end opening portion

  17 opens on the distal end face of the

  distal end portion

  6, whereas the present embodiment adopts a configuration in which the channel distal

  end opening portion

  17 is provided in the

  support portion

  18 in which the

  shielding section

  18a is formed.

• The channel distal

  end opening portion

  17 communicates with a

  conduit

  17b that forms a channel provided inside the insertion portion 4 (including the distal end portion 6) via a

  conduit

  17a inside the

  support portion

  18.

• Furthermore, although the

  cylindrical portion

  10 is provided at a position decentered from the center position of the

  distal end portion

  6 according to the first embodiment, the

  cylindrical portion

  10 is provided in the center position of the

  distal end portion

  6 in the present embodiment.

• Furthermore, although the

  support portion

  18 is provided in a direction slightly deviated from the direction right below the

  cylindrical portion

  10 in the first embodiment, the

  support portion

  18 is provided in a direction right below the

  cylindrical portion

  10 in the present embodiment.

• Furthermore, as with the first embodiment, the forward

  viewing illuminating window

  16 is provided on the distal end face of the

  distal end portion

  6, but the forward

  viewing illuminating window

  16 is provided in a position closer to the top in the present embodiment.

• As shown in

  Fig. 8

  , the

  shielding section

  18a of the

  support portion

  18 provides shielding, for example, at an angle of α around an optical axis of an objective

  optical system

  11, that is, an image pickup center O in the circumferential direction. A forward viewing observation

  window nozzle portion

  19, a forward

  viewing illuminating window

  21, a side viewing observation

  window nozzle portion

  22 and the channel distal

  end opening portion

  17 are provided in the

  support portion

  18 so as to fall within the angle of α. The rest of the configuration is similar to that of the first embodiment.

• The present embodiment basically has effects similar to those of the first embodiment, but has operations or effects different from the operations or effects when a treatment instrument is used.

• In the first embodiment, when the surgeon causes the treatment instrument to protrude from the channel distal

  end opening portion

  17, the protruding treatment instrument appears within the side viewing field of the side

  viewing observation window

  13, and therefore the treatment instrument is observed as a side viewing field image.

• By contrast, in the present embodiment, the portion of the

  conduit

  17a into which the treatment instrument is inserted that appears within the side viewing field of the side

  viewing observation window

  13 is shielded by the

  shielding section

  18a, and therefore even when the treatment instrument is inserted, this does not appear in a side viewing field image. For example,

  Fig. 7

  illustrates the distal end portion of a

  treatment instrument

  56 protruding up to the vicinity of the channel distal

  end opening portion

  17, but the distal end side of the

  treatment instrument

  56 does not appear in a side viewing field image.

• The distal end side of the

  treatment instrument

  56 has a high function of reflecting light, and therefore if this enters the side viewing field just near the side

  viewing observation window

  13, a high luminance image results, and thus if a condition is set for performing automatic light adjustment, the function of automatic light adjustment is reduced. Furthermore, the high luminance may produce flare in the endoscope image which is an observed image.

• Therefore, even when the

  treatment instrument

  56 is used, according to the present embodiment, an excellent endoscope image can be obtained and also the automatic light adjustment function can be used without deterioration.

• The endoscope image displayed on a

  display surface

  35a of a

  monitor

  35 of the present embodiment is as shown in

  Fig. 9

  . Since

  Fig. 9

  bears close resemblance to the case in

  Fig. 6

  , components are shown assigned the same reference numerals as those in

  Fig. 6

  .

• The present embodiment has effects similar to those of the first embodiment. Furthermore, also even when the

  treatment instrument

  56 is used, it is possible to obtain an endoscope image having an excellent side viewing field image.

• To be more specific, according to the present embodiment, the

  shielding section

  18a of the

  support portion

  18 shields the forward viewing observation

  window nozzle portion

  19, the forward

  viewing illuminating window

  21, the side viewing observation

  window nozzle portion

  22 and the

  conduit

  17a into which the

  treatment instrument

  56 is inserted as protruding members different from the original observation target appearing within the side viewing field of the side

  viewing observation window

  13 so as not to be acquired as side viewing field images, and it is thereby possible to generate an excellent side viewing field image.

• Therefore, the surgeon observes an endoscope image having an excellent side viewing field image, and can thereby smoothly perform an inspection of tubular organs or the like.

• Furthermore, according to the present embodiment, when the

  treatment instrument

  56 is used, and even if an image signal of the

  image pickup device

  34 is used for automatic light adjustment, the image signal of the side viewing field image is an image signal not affected by the protruding member, and therefore automatic light adjustment can be effectively used without deterioration of the function.

• The outside diameter of the

  support portion

  18 need not be the same as the outside diameter of the

  distal end portion

  6. Furthermore, although the

  support portion

  18 is provided at one location in the direction below the

  cylindrical portion

  10, the

  support portions

  18 may also be provided at a plurality of locations.

• Furthermore, when the distal end side of the

  treatment instrument

  56 is made to protrude further toward the distal end side so as to fall within the forward viewing field of the forward

  viewing observation window

  12, it is possible to observe the distal end side of the

  treatment instrument

  56 through the forward

  viewing observation window

  12.

• In this case, the luminance level of the image signal of the forward viewing field image is influenced by the high luminance portion of the distal end side of the

  treatment instrument

  56, but at least the side viewing field image is designed not to be thereby influenced and there is an effect of being able to reduce the influences compared to the case where both images have influences.

(Third embodiment)

• Next, a third embodiment of the present invention will be described.

  Fig. 10

  illustrates a perspective view of a configuration in the vicinity of a

  distal end portion

  6 of an

  insertion portion

  4 of an endoscope of the third embodiment of the present invention and

  Fig. 11

  illustrates a front view thereof.

• The present embodiment provides shielding

  sections

  61a and 61b on the outer surface of a side

  viewing observation window

  13 so that light from protruding members that protrude from the distal end face of the

  distal end portion

  6 and enter the side viewing field of the side

  viewing observation window

  13 does not enter the side viewing field of the side

  viewing observation window

  13.

• A

  cylindrical portion

  10 having a cylindrical shape is provided in the center of the distal end face of the

  distal end portion

  6. As with the second embodiment, the

  cylindrical portion

  10 is provided with a forward

  viewing observation window

  12, the side

  viewing observation window

  13 and a side

  viewing illuminating window

  14.

• A side viewing observation

  window nozzle portion

  62 and a forward

  viewing illuminating window

  21 are provided as protruding members so as to protrude at positions in the upper part of the

  cylindrical portion

  10 on the distal end face of the

  distal end portion

  6 and furthermore, a forward viewing observation

  window nozzle portion

  19 is provided as a protruding member so as to protrude at a position in the lower part of the

  cylindrical portion

  10. Furthermore, a channel distal

  end opening portion

  17 is provided neighboring the forward viewing observation

  window nozzle portion

  19 on the distal end face of the

  distal end portion

  6.

• Furthermore, the shielding

  sections

  61a and 61b for shielding light from the protruding members so as not to enter the side viewing field of the side

  viewing observation window

  13 are provided on the side of the upper part and the side of the lower part provided with the protruding members of the side

  viewing observation window

  13.

• Although the

  shielding sections

  61a and 61b can be made up of a film-like member by applying a black paint to the side

  viewing observation window

  13 in a film shape, the present invention is not limited thereto, but a metal having a high light-shielding function or the like may be formed in a film shape through vapor deposition on the side

  viewing observation window

  13 or a black sheet or a sheet having a high light-shielding function may be adhered and attached to the side

  viewing observation window

  13.

• As shown in

  Fig. 11

  , the shielding

  sections

  61a and 61b provide shielding at angles α1 and α2 respectively around an image pickup center O. Therefore, light from the side viewing observation

  window nozzle portion

  62 and the forward viewing illumination section 63 is shielded by the

  shielding section

  61a and light from the forward viewing observation

  window nozzle portion

  19 is shielded by the

  shielding section

  61b and does not enter the side

  viewing observation window

  13.

• Furthermore, according to the present embodiment, also even when a treatment instrument protrudes from the channel distal

  end opening portion

  17, light from the treatment instrument can be shielded by the shielding

  section

  61 b. The rest of the configuration is similar to that of the aforementioned first or second embodiment.

• An endoscope image displayed on a

  display surface

  35a of a

  monitor

  35 in the case of the present embodiment is as shown in

  Fig. 12

  . As shown in

  Fig. 12

  , shielding

  regions

  54a and 54b corresponding to the

  shielding sections

  61a and 61b shown in

  Fig. 11

  are formed in a

  display region

  53 of the side viewing field image.

• In substantially the same way as the second embodiment, according to the present embodiment, the protruding members that protrude from the distal end face of the

  distal end portion

  6 are shielded so as not to be acquired by the side

  viewing observation window

  13 as an image, and thereby an endoscope image having an excellent side viewing field image can be acquired.

• Furthermore, even when the treatment instrument is used and the distal end side of the treatment instrument is made to protrude from the channel distal

  end opening portion

  17, shielding can be provided by the

  shielding section

  61b, and it is thereby possible to prevent the occurrence of flare and use automatic light adjustment without deterioration of the function.

• Furthermore, according to the present embodiment, the film-

  like shielding sections

  61a and 61b are provided in the side

  viewing observation window

  13, and thereby effects similar to those of the second embodiment are realized at low cost (except the support function).

• Fig. 13

  illustrates a configuration of a

  distal end portion

  6 of an

  insertion portion

  4 of an endoscope according to a first modification example of the present embodiment. The present modification example adopts a configuration replacing the aforementioned film-

  like shielding sections

  61a and 61b provided in the side

  viewing observation window

  13 by shielding

  plates

  71a and 71b having a shielding function protruding toward the distal end side more than the side

  viewing observation window

  13 along the side of the

  cylindrical portion

  10 from the distal end face of the

  distal end portion

  6.

• That is, the

  shielding plates

  71a and 71b are arranged over the entire viewing field from the proximal end side to the distal end side of the side

  viewing observation window

  13, that is, from the side viewing rear side to the side viewing forward side of the side

  viewing observation window

  13.

• In this case, the

  shielding plates

  71a and 71 b, and the side

  viewing observation window

  13 may be adhered together using an adhesive. Furthermore, delustering or lusterless paint may be applied to the inner surface on the side

  viewing observation window

  13 side of the

  shielding plates

  71a and 71b. Furthermore, as described above, a metal such as stainless steel having a high light-shielding function or resin such as polysulfone resin provided with a light-shielding function may be used. The present modification example has substantially the same effect as that of the third embodiment.

• As a second modification example of the present embodiment, the

  shielding section

  61b may be formed to prevent light from the forward viewing observation

  window nozzle portion

  19 from entering the side

  viewing observation window

  13. In the case of the present modification example, when a treatment instrument is used, the treatment instrument exerts an influence, but in the case of application with a small frequency of use of the treatment instrument, a side viewing observation window having a wider side viewing field can be realized.

• Furthermore, the present second modification example may be applied to the above described first modification example.

(Fourth embodiment)

• Next, a fourth embodiment of the present invention will be described.

  Fig. 14

  illustrates a front view of a

  distal end portion

  6 of an

  insertion portion

  4 of an endoscope according to the fourth embodiment of the present invention.

• A

  cylindrical portion

  10 is provided in the center of a distal end face of the

  distal end portion

  6 and a channel distal

  end opening portion

  17 is provided therebelow. Furthermore, a forward viewing observation

  window nozzle section

  19, a side viewing observation

  window nozzle portion

  62 and a forward

  viewing illuminating window

  21 are provided so as to protrude as protruding members at diagonally lower positions neighboring the

  cylindrical portion

  10 on the distal end face of the

  distal end portion

  6.

• These protruding members and the channel distal

  end opening portion

  17 are arranged within an angle of, for example, β1round an image pickup center O and the protruding members alone are arranged within an angle of β2 around the image pickup center O.

• On the other hand, a

  video processor

  32D as an image processing apparatus to which an

  endoscope

  2D provided with the

  distal end portion

  6 is detachably connected incorporates a

  signal processing section

  81 that performs signal processing on an image signal outputted from an

  image pickup device

  34 as shown in

  Fig. 15

  and the video signal as an image signal for display generated by the

  signal processing section

  81 is outputted to a

  monitor

  35. The endoscope having an

  insertion portion

  4 provided with a distal end portion different from the arrangement structure of the

  distal end portion

  6 shown in

  Fig. 14

  is also detachably connected to the

  video processor

  32D.

• The

  signal processing section

  81 is provided with a

  mask processing section

  81a that performs signal processing (referred to as "mask processing") of electrically masking (shielding) a portion corresponding to the protruding member of the image signal portion by the side

  viewing observation window

  13 in the image signal of the

  image pickup device

  34. The

  mask processing section

  81a performs mask processing corresponding to a control signal from a

  control section

  82.

• Furthermore, the

  endoscope

  2D has an

  ID generation section

  83 that generates identification information (ID information) specific to the

  endoscope

  2D and when the

  endoscope

  2D is connected to the

  video processor

  32D, the ID information is inputted to an

  ID identification section

  84 provided in the

  video processor

  32D.

• The

  ID identification section

  84 sends the identified ID information to the

  control section

  82 and the

  control section

  82 generates a control signal corresponding to the ID information and controls mask processing of the

  mask processing section

  81a.

• The ID information includes arrangement information of protruding members and the channel distal

  end opening portion

  17 appearing in the side viewing field in the

  distal end portion

  6 of the

  endoscope

  2D and the

  mask processing section

  81a performs mask processing corresponding to the arrangement information of the protruding members and channel distal

  end opening portion

  17 based on the ID information.

• A configuration may also be adopted which includes inside the

  video processor

  32D (e.g., inside the

  mask processing section

  81a) arrangement information recording means such as a lookup table for reading arrangement information of the protruding members and channel distal

  end opening portion

  17 appearing in the side viewing field of the

  distal end portion

  6 of the

  endoscope

  2D for which the ID information is generated from the ID information.

• When the treatment instrument is not inserted into the channel, the treatment instrument protruding from the channel does not appear in the side viewing field. For this reason, the

  mask processing section

  81a performs mask processing corresponding to the arrangement information of at least the protruding members based on the ID information so as to allow the operator to select whether or not to perform mask processing corresponding to the arrangement information of the channel distal

  end opening portion

  17.

• Furthermore, the

  control section

  82 is connected to an input apparatus such as a

  keyboard

  36 and the operator such as the surgeon can input from the

  keyboard

  36 an instruction on ON/OFF of mask processing operation, mask shape generated through mask processing and mask region or the like and the

  control section

  82 controls the operation of the

  mask processing section

  8 1a in accordance with the instruction inputted.

• Therefore, the input apparatus such as the

  keyboard

  36 has the function of switching instruction means for instructing switching ON/OFF the mask processing operation. The

  video processor

  32D including the

  keyboard

  36 has the function of switching means for switching ON/OFF the mask processing operation.

• The input apparatus as the switching instruction means may also be a foot switch, a switch on the operation panel of the video processor or a

  scope switch

  25 or the like in addition to the

  keyboard

  36.

• The

  signal processing section

  81 outputs a video signal corresponding to the mask processing by the

  mask processing section

  81a to the

  monitor

  35. Furthermore, the

  signal processing section

  81 calculates average luminance corresponding to the brightness of the endoscope image from the video signal subjected to mask processing and outputs a light adjustment signal for light adjustment of the light to appropriate brightness to a

  light source apparatus

  31. The

  signal processing section

  81 outputs, for example, a difference signal from a reference brightness value corresponding to appropriate brightness to the

  light source apparatus

  31 as a light adjustment signal.

• The

  light source apparatus

  31 adjusts the light quantity from a

  lamp

  85 as a light source using a

  diaphragm

  86 that can adjust the amount of opening/closing, condenses the light using a

  lens

  87 and supplies the light to a

  light guide

  88 as a light guide member of illuminating light. In this case, by automatically adjusting the amount of opening/closing of the

  diaphragm

  86 through a light adjustment signal, the quantity of illuminating light supplied to the

  light guide

  88 is automatically adjusted (automatic light adjustment).

• By automatically adjusting the amount of opening/closing of the

  diaphragm

  86 through the light adjustment signal in this way, the amount of illuminating light supplied to the

  light guide

  88 is adjusted so as to maintain the brightness value (luminance level) in the case of appropriate brightness.

• When, for example, the average luminance level of the endoscope image displayed is brighter than a brightness value in the case of appropriate brightness, the amount of opening/closing of the

  diaphragm

  86 is controlled so as to decrease through a light adjustment signal in that case and adjusted so as to maintain the brightness value in the case of appropriate brightness.

• Fig. 16A

  shows an endoscope image when mask processing by the

  mask processing section

  81a is set to OFF. In this case, the endoscope image not under mask processing is displayed in a

  display region

  52 for forward viewing field images and a

  display region

  53 for side viewing field images.

• On the other hand,

  Fig. 16B

  illustrates an endoscope image when mask processing corresponding to ID information by the

  ID generation section

  83 is applied. In the case of

  Fig. 16B

  , in correspondence with the arrangement information of the protruding members and channel distal

  end opening portion

  17, the display region portion in which the protruding members and the channel distal

  end opening portion

  17 are displayed in the

  display region

  53 for side viewing field images constitutes a

  masked section

  89a where those images are electrically masked which is a non-display region where no image in the region of the

  masked section

  89a is displayed.

• Thus, according to the present embodiment, it is possible to shield images of protruding members appearing in the side viewing field of the side

  viewing observation window

  13 through electric signal processing so as not to be displayed in an endoscope image.

• Therefore, as the endoscope image displayed on the

  monitor

  35, the present embodiment has effects similar to those when shielding is provided by the shielding section provided on the endoscope side as with the aforementioned first to third embodiments.

• Furthermore, the present embodiment adopts the configuration in which a light adjustment signal can be generated from a video signal subjected to mask processing, and can thereby use the light adjustment function not only for protruding members but also when the treatment instrument is used without deterioration of the light adjustment function.

• As a supplementary explanation, as described in the section of related arts, when the nozzle as a protruding member appears in a side viewing field image of short distance, the luminance level of an image signal (video signal) of the image of the original observation target rises due to the image of the nozzle, deteriorating the light adjustment function. However, the present embodiment generates a light adjustment signal from a video signal obtained by applying mask processing to the image of the protruding member in the side viewing field image, and can thereby prevent deterioration of the light adjustment function. Furthermore, even when the treatment instrument protrudes from the channel distal

  end opening portion

  17, this functions as in the case of the protruding member. This treatment instrument can also be regarded as a protruding member.

• Furthermore, in the present embodiment, the surgeon can input an instruction so as to perform mask processing corresponding to the arrangement information of only the protruding members from the

  keyboard

  36. When this instruction is inputted, as shown in

  Fig. 17

  , it is possible to form a non-display region by a

  masked section

  89b corresponding to the arrangement information of only the protruding members.

• Therefore, when not using any treatment instrument, if the surgeon inputs an instruction so as to generate the

  masked section

  89b corresponding to the arrangement information of only the protruding members, the display region of the side viewing field image can be broadened.

• Furthermore, in the case of an endoscope where the endoscope itself does not have the function of the shielding section, if the surgeon inputs an instruction so as to perform mask processing appropriate for the endoscope from the input apparatus such as the

  keyboard

  36, the

  mask processing section

  81a generates a masked section subjected to mask processing in accordance with the instruction inputted. Therefore, the surgeon can generate a desired masked section and perform endoscopy with the endoscope image in which the masked section is formed. Thus, the present embodiment enables the region in which a masked section is formed to be changed.

• An embodiment configured by partially combining the aforementioned embodiments or the like also belongs to the present invention. For example, it is possible to adopt a configuration combining the fourth embodiment with the first to third embodiment(s). Such a configuration may include a configuration where the protruding members appearing in the side viewing field image are mechanically shielded on the endoscope side and a configuration where the protruding members are electrically shielded on the image processing apparatus side.

• For example, in the endoscope having the configuration shown in

  Fig. 13

  , a shielding section for mechanical shielding is formed of the

  shielding plates

  71a and 71b provided on the endoscope, but in the case of an endoscope not provided with the

  shielding plates

  71a and 71 b, electrical shielding is provided on the image processing apparatus side.

• Furthermore, for example, in the endoscope having the configuration shown in

  Fig. 13

  , when the treatment instrument protrudes from the channel distal

  end opening portion

  17 and this treatment instrument constitutes a protruding member, the treatment instrument can be electrically shielded on the image processing apparatus side by inputting an instruction for performing mask processing from the

  keyboard

  36.

• The present application is filed claiming the priority of Japanese Patent Application No.

  2009-255188

  filed in Japan on November 6, 2009, and the above described disclosure is incorporated by reference in the present description and claims.

1. An endoscope apparatus comprising:

   an insertion portion inserted into an observation target;

   a side viewing observation section provided on a distal end side of the insertion portion for acquiring a subject image of an observation target in a circumferential direction of the insertion portion;

   a forward viewing observation section provided closer to the distal end side than the side viewing observation section of the insertion portion for acquiring a subject image of an observation target in an insertion direction of the insertion portion;

   a protruding member that passes within a viewing field of the side viewing observation section and protrudes closer to the distal end side than the side viewing observation section;

   an image processing apparatus that generates a side viewing observed image and a forward viewing observed image to be displayed as observed images based on the subject image in the circumferential direction obtained from the side viewing observation section and the subject image in the insertion direction obtained from the forward viewing observation section; and

   a shielding section that electrically or mechanically shields a display of a subject image of an observation target in a range in which the protruding member is located on the side viewing field image, when the observed images generated by the image processing apparatus are displayed.

2. The endoscope apparatus according to claim 1, wherein the shielding section comprises a mask processing section provided in the image processing apparatus that forms a masked section electrically shielded through signal processing on an image portion in a range in which the protruding member is located on the side viewing field image generated by the image processing apparatus.

3. The endoscope apparatus according to claim 2, wherein an endoscope having the insertion portion is detachably connected to the image processing apparatus, and
   the mask processing section can change a region in which the masked section is formed according to identification information specific to the endoscope connected to the image processing apparatus.

4. The endoscope apparatus according to claim 3, wherein the image processing apparatus further comprises a switching section that switches between processing that forms the masked section and processing that does not form the masked section.

5. The endoscope apparatus according to claim 1, wherein the shielding section comprises a shielding member arranged in the side viewing observation section for mechanically shielding light entering a predetermined range of the side viewing observation section.

6. The endoscope apparatus according to claim 2, wherein the side viewing observation section and the forward viewing observation section protrude from a distal end face of the insertion portion, and are provided in a cylindrical member having a smaller diameter than an outside diameter of the insertion portion,
   the cylindrical member further comprises an objective optical system comprising:

   a rotationally symmetric first lens arranged along a central axis of the cylindrical member for forming a subject image in the insertion direction; and

   a second lens arranged behind the first lens and connected to a mirror lens having a mirror surface for refracting light passing through the first lens and forming a subject image in the insertion direction and forming a subject image in the circumferential direction, and

   an image pickup surface of an image pickup device is arranged at an image forming position of the objective optical system.

7. The endoscope apparatus according to claim 5, wherein the side viewing observation section and the forward viewing observation section protrude from a distal end face of the insertion portion, and are provided in a cylindrical member having a smaller diameter than an outside diameter of the insertion portion,
   the cylindrical member further comprises an objective optical system comprising:

   a rotationally symmetric first lens arranged along a central axis of the cylindrical member for forming a subject image in the insertion direction; and

   a second lens arranged behind the first lens and connected to a mirror lens having a mirror surface for refracting light passing through the first lens and forming a subject image in the insertion direction and forming a subject image in the circumferential direction, and

   an image pickup surface of an image pickup device is arranged at an image forming position of the objective optical system.

8. The endoscope apparatus according to claim 6, wherein the objective optical system forms a subject image in the insertion direction in a circular region in a center of the image pickup surface of the image pickup device and forms a subject image in the circumferential direction in a ring region of an outer circumference of the circular region, and
   the image processing apparatus generates the forward viewing observed image and the side viewing observed image from image signals of the circular region and the ring region photoelectrically converted by the image pickup device.

9. The endoscope apparatus according to claim 7, wherein the objective optical system forms a subject image in the insertion direction in a circular region in a center of the image pickup surface of the image pickup device and forms a subject image in the circumferential direction in a ring region of an outer circumference of the circular region, and
   the image processing apparatus generates the forward viewing observed image and the side viewing observed image from image signals of the circular region and the ring region photoelectrically converted by the image pickup device.

10. The endoscope apparatus according to claim 8, wherein the mask processing section forms the masked section in response to an instruction input for mask processing corresponding to arrangement information of the protruding member from an input apparatus.

11. The endoscope apparatus according to claim 8, wherein an endoscope having the insertion portion is detachably connected to the image processing apparatus, and
    the mask processing section forms the masked section corresponding to the protruding member provided in the insertion portion from identification information specific to the endoscope connected to the image processing apparatus.

12. The endoscope apparatus according to claim 8, wherein an endoscope having the insertion portion provided with a channel into which a treatment instrument can be inserted is detachably connected to the image processing apparatus, and
    the mask processing section forms the masked section corresponding to the protruding member for a case where the treatment instrument protruding from a distal end opening portion of the channel constitutes the protruding member located in the side viewing field image.

13. The endoscope apparatus according to claim 8, wherein the image processing apparatus generates a light adjustment signal for light adjustment of a light quantity of illuminating light of a light source apparatus supplied to a light guide member of an endoscope from a video signal subjected to mask processing forming the masked section by the mask processing section.

14. An endoscope comprising:

    an insertion portion inserted into an observation target;

    a side viewing observation section provided on a distal end side of the insertion portion for allowing light from the observation target in a circumferential direction of the insertion portion to enter and acquiring a subject image;

    a forward viewing observation section provided closer to a distal end side than the side viewing observation section in the insertion portion for allowing light from the observation target in an insertion direction of the insertion portion to enter and acquiring a subject image;

    a protruding member that passes within a viewing field of the side viewing observation section and protrudes closer to the distal end side than the side viewing observation section;

    a protruding member that passes within a viewing field of the side viewing observation section and protrudes closer to the distal end side than the side viewing observation section; and

    a shielding section located within a viewing field of the side viewing observation section, which shields light entering the side viewing observation section in a range in which at least the protruding member passes within the side viewing field.

15. The endoscope according to claim 14, wherein the shielding section is disposed at a predetermined position inside the side viewing observation section over an entire length at least from a proximal end to a distal end of the side viewing observation section.

16. The endoscope according to claim 15, wherein the shielding section comprises a conduit into which the protruding member is inserted and an opening portion that communicates with the conduit and opens at an end face closer to the distal end side than the side viewing observation section.

17. The endoscope according to claim 15, wherein the side viewing observation section comprises a ring-shaped observation window formed on an entire perimeter of a side of the insertion portion.

18. The endoscope according to claim 15, wherein the protruding member comprises a nozzle that injects a liquid for cleaning an observation window of the forward viewing observation section.

19. The endoscope according to claim 16, wherein the conduit of the shielding section is a channel into which a treatment instrument can be inserted, and
    the protruding member is a treatment instrument that is inserted into the channel and protrudes up to within a viewing field of the forward viewing observation window.

20. The endoscope according to claim 17, wherein the shielding section is made of a light-shielding film-like member arranged on an outer surface of the ring-shaped observation window.